Statistical y-decay spectra from excited nuclear states are calculated.The spectra reflect the perturbation of the level density by pair correlations and, hence, the stepwise weakening of the pair correlations with increasing quasiparticle number. The level density is obtained by counting manyquasiparticle states from a self-consistent BCS calculation or from a diagonalization of particle numberprojected states. The calculated spectra resemble measured spectra from the decay out of superdeformed bands, but have only -70% of the measured intensity. PACS numbers: 21.10.Ma, 21.60.Ka, 23.20.Lv, 27.80.+w Pair correlations are essential for describing many properties of the low-lying states of nuclei. By applying methods developed to describe superAuidity and superconductivity in condensed matter physics, one can explain the observed moments of inertia of ground state rotational bands, as well as the occurrence of a gap in the energy spectrum of even nuclei between the ground and excited states [1]. With increasing temperature, pair correlations become weaker, and are finally completely quenched, in analogy with the superAuid to normal phase transition in liquids. Because of the mesoscopic (i.e., finite) nature of the nucleus, pairing correlations can be appreciably re-

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The single-particle character of states outside the doubly magic (radioactive) nucleus 56 Ni has been determined through a measurement of the ͑d, p͒ neutron transfer reaction using inverse kinematics. From the spectroscopic factors of the low-lying states in 57 Ni, the astrophysically interesting yield for the 56 Ni͑p, g͒ reaction to the mirror nucleus 57 Cu has been calculated, utilizing charge symmetry. The rate for this reaction in the temperature range typical of novae, supernovae, and x-ray bursts is found to be more than 10 times higher than previously assumed. [S0031-9007 (97)05085-0]